1. Field of the Invention
The present invention relates to a pneumatic and electronic control system for an electronically powered air purifying respirator system.
2. Description of Related Art
Respiratory devices, such as protection masks, also interchangeably referred to herein as gas masks or masks, are well known. Civilians, law enforcement, military personnel, fire fighters and other groups of individuals commonly referred to as first responders, hereinafter referred to as users, wear masks for protection from an environment containing harmful and possibly fatal air-born toxins or any other such hazardous material. Such toxins and materials are hazardous to respiratory systems and generally take the form of harmful gases, vapors, and particulate matter. The respiratory hazards may also include various agents, such as nuclear, biological and chemical (NBC) agents, which may be in the form of particulates, vapors or aerosols.
One type of breathing apparatus, known as a Powered Air Purifying Respirator (PAPR), is a fan-forced positive pressure breathing apparatus. PAPRs are used in environments where the ambient air is relatively oxygen-rich and where filtering elements are effective in removing all contaminants from the ambient air before the ambient air enters the gas mask. PAPRs typically include a gas mask, a filtering element to remove contaminants from ambient air, a blowing element, such as a fan and a power source to provide operational power to the blowing element. The fan or blowing element continuously supplies filtered air to the gas mask. The filtered air replenishes the internal space of the mask, and exhaled air, also known as spent air, is continually ejected.
Conventional PAPRs have numerous drawbacks that limit their applicability. For example, the continuous supply of filtered air to the user is highly inefficient and wasteful because the user is unable to ingest and/or inhale all of the continuously filtered air, which is fed into the internal space of the gas mask. It is well understood to those skilled in the art that during exhalation, the user cannot ingest or inhale the filtered air. However, even during exhalation, filtered air continually enters the internal space of the mask in typical PAPRs. As a result, air exhaled by the user and some amount of unused, filtered air driven into the internal space of the mask by the blowing element are expelled from the mask during the exhalation phase of the user's breathing cycle. Thus, the PAPR exerts resources, specifically energy from the power source, to supply filtered air into the internal space of the mask without a productive or otherwise efficient use of that air, such as ingestion or inhalation by the user.
Another limitation of conventional PAPR's is that the air exhaled by the user and the filtered air driven into the internal space of the mask by the blowing element, respectively, flow in opposite or at least countervailing directions relative to each other within the internal space of the mask. The opposite air flow creates counteracting forces in the internal space of the mask. As a result, the user's workload to draw, inhale, or ingest filtered air during breathing increases. The increased breathing workload means that the user endures difficulty while breathing and is otherwise uncomfortable while using such conventional PAPRs.
Another drawback of conventional PAPRs include the continuous supply of filtered air creating undue wear and tear on the working components of the PAPR. Moreover, the continuous operation of the components that filter the air supplied to the internal space of the mask typically results in mechanical breakdown of the components of the PAPR. The more the components of the PAPR are used, the more frequent such breakdowns are likely to occur. For example, the filtering element becomes full of contaminants over time and must be replaced. Replacement of the filter directly correlates to the amount of air to be filtered. Typically, in conventional PAPRs, air is continually pumped to the internal space of the mask. The filter required to remove contaminants from the ambient air works continually as well. Accordingly, the filter requires frequent and regular replacement. If the air requiring filtering were to be intermittently supplied when needed by the user, the filter would have to be replaced less frequently.
A similar situation exists with respect to the power supply of conventional PAPRs. An energy source with limited capacity to generate power is typically used to drive the filtering components. In general, the amount of reserve power available in an energy source of the conventional PAPR is inversely proportional to the amount of air being filtered and driven by the blowing element. Typically, in conventional PAPRs, the energy source for the PAPR is constantly used, and reserves are exhausted, as the continual filtering of the supply of air to the mask occurs. Less power from the energy source is used if the air is intermittently filtered. The less power used, the more battery power that is conserved. As a result, the battery has longer life and is ultimately replaced less often with intermittent filtering.
There is a need for a PAPR mask that improves the air flow within the mask and facilitates breathing for the user. There is a further need for a PAPR mask that conserves power and extends the life of the energy source powering the mask.